The present invention relates generally to keypads and more particular to membrane keypads. A membrane keypad is a relatively thin switch array which is provided with a plastic membrane cover. The use of such a keypad is considered advantageous where space is to be conserved or it is desired to provide a sealed keypad.
In the past, there has been a desire to provide illumination for keypads where electric devices are to be used in low light situations and where contrast is desired to be improved. Additionally, it has been desired to use illumination as an indicator of circuit operation or readiness. The desire for illumination has been partially addressed in some devices by the placement of a signaling lamp adjacent the key site.
Other means of illumination have been offered such as shown in U.S. Pat. No. 4,811,175 which discloses an illuminated switch in which light may pass through a translucent switch cover. The light from the source placed at the interior of the switch passes through the switch and illuminates the area to be pressed. This type of construction, at times, may restrict the placement of the keys or switches.
Other ways for creating illuminated switches are with a dome having a single hole through which the light source may protrude. This type of illumination could be incompatible with some keypads since the light source placement may interfere with the operation of the switch actuator.
Additional needs include low profile, high contrast switch assemblies and a way to create a targeting effect for a particular keypad switch.
The present invention is directed to overcome the aforementioned problems and disadvantages associated with prior art illuminated keypads wherein it is desired to provide a transparent area about the switch illuminated with reflected light.